Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine blade assembly for producing power. Combustors often operate at high temperatures that may exceed 2,500 degrees Fahrenheit. Typical turbine combustor configurations expose turbine blade assemblies to these high temperatures. As a result, turbine blades must be made of materials capable of withstanding such high temperatures.
A turbine blade is formed from a root portion at one end and an elongated portion forming a blade that extends outwardly from a platform coupled to the root portion at an opposite end of the turbine blade. The blade is ordinarily composed of a tip opposite the root section, a leading edge, and a trailing edge. The tip of a turbine blade often has a tip feature to reduce the size of the gap between ring segments and blades in the gas path of the turbine to prevent tip flow leakage, which reduces the amount of torque generated by the turbine blades. Some turbine blades include outer shrouds, as shown in FIG. 1, attached to the tips. Tip leakage loss, as shown in FIG. 2, is essentially lost opportunity for work extraction and also contributes towards aerodynamic secondary loss. To reduce overtip leakage, shrouded blades typically include a circumferential knife edge for running tip gaps. One of the major loss mechanisms on shrouded turbine stages is the cavity loss, in particular, the mixing loss due to reentry of tip shroud leakage flow, as shown in FIG. 2, from the cavity into the main gas path. Overtip leakage flow is not turned by the rotor blade, hence leaving the shroud cavity with relatively high swirl velocity and at an angular mismatch with main gas flow. This mismatch in flow angle and velocities result in aerodynamic mixing loss.